Trials and tribulations in the first three years in operation of the SSAMS for biomedical 14C-AMS at LLNL
Abstract
We report on the first several years of operation of our recently installed 250 kV SSAMS at LLNL, purchased to replace our 1-MV AMS system for the measurement of 14C from labeled biochemical samples. We have modified the ion source region to improve ion output. Additionally, the SSAMS required significant software modifications to the data acquisition system in order to accurately measure 14C at the high-count rates typically encountered with labeled biochemical samples. Here, we found that the data can be corrected assuming a nonparalyzable dead time response with a single event dead time of 6 µs. Since operation began, we have measured over 13,000 graphitic unknowns and over 1900 standards with an overall precision of 1.0%. We have optimized our system for the analysis of CO2 gas samples. We compared aliquots of identical samples measured as solid graphite and as liquid drops. Excellent agreement was found between the two, although the average precision of the graphite targets was an order of magnitude better than the liquid drop analysis due to the much larger number of 14C atoms available for measurement.
- Authors:
-
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Center for Accelerator Mass Spectrometry
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Biology and Biotechnology Division
- Publication Date:
- Research Org.:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA)
- OSTI Identifier:
- 1488813
- Report Number(s):
- LLNL-JRNL-741335
Journal ID: ISSN 0168-583X; 895864
- Grant/Contract Number:
- AC52-07NA27344
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
- Additional Journal Information:
- Journal Volume: 438; Journal Issue: C; Journal ID: ISSN 0168-583X
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 43 PARTICLE ACCELERATORS; 42 ENGINEERING
Citation Formats
Ognibene, T. J., Haack, K. W., Bench, G., and Turteltaub, K. W. Trials and tribulations in the first three years in operation of the SSAMS for biomedical 14C-AMS at LLNL. United States: N. p., 2018.
Web. https://doi.org/10.1016/j.nimb.2018.05.008.
Ognibene, T. J., Haack, K. W., Bench, G., & Turteltaub, K. W. Trials and tribulations in the first three years in operation of the SSAMS for biomedical 14C-AMS at LLNL. United States. https://doi.org/10.1016/j.nimb.2018.05.008
Ognibene, T. J., Haack, K. W., Bench, G., and Turteltaub, K. W. Thu .
"Trials and tribulations in the first three years in operation of the SSAMS for biomedical 14C-AMS at LLNL". United States. https://doi.org/10.1016/j.nimb.2018.05.008. https://www.osti.gov/servlets/purl/1488813.
@article{osti_1488813,
title = {Trials and tribulations in the first three years in operation of the SSAMS for biomedical 14C-AMS at LLNL},
author = {Ognibene, T. J. and Haack, K. W. and Bench, G. and Turteltaub, K. W.},
abstractNote = {We report on the first several years of operation of our recently installed 250 kV SSAMS at LLNL, purchased to replace our 1-MV AMS system for the measurement of 14C from labeled biochemical samples. We have modified the ion source region to improve ion output. Additionally, the SSAMS required significant software modifications to the data acquisition system in order to accurately measure 14C at the high-count rates typically encountered with labeled biochemical samples. Here, we found that the data can be corrected assuming a nonparalyzable dead time response with a single event dead time of 6 µs. Since operation began, we have measured over 13,000 graphitic unknowns and over 1900 standards with an overall precision of 1.0%. We have optimized our system for the analysis of CO2 gas samples. We compared aliquots of identical samples measured as solid graphite and as liquid drops. Excellent agreement was found between the two, although the average precision of the graphite targets was an order of magnitude better than the liquid drop analysis due to the much larger number of 14C atoms available for measurement.},
doi = {10.1016/j.nimb.2018.05.008},
journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms},
number = C,
volume = 438,
place = {United States},
year = {2018},
month = {5}
}
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Figures / Tables:
Table 1: Measured Fraction Modern values along with fitted values, assuming a Gaussian distribution, of secondary standards measured on the SSAMS as presented in Figure 7.